Invisible Places 18–20JULY 2014, VISEU, PORTUGAL Resounding Overbetuwe. An acoustic gradient in a sustainable transport corridor Rosanne Weijers [email protected] Student Landscape Architecture at Wageningen Univerisity, Netherlands Abstract Overbetuwe, a region in the Netherlands, functions as a transport corridor. The presence of large-scale infrastructure causes noise nuisance and make the landscape in Overbetuwe unpleasant be in. New functions with noise sensitive facades are planned, while the pres- ence of traffic noise will increase due the A15 expansion of 2x3 ways. Meanwhile the Over- betuwe municipality strives to reach climate neutrality by the year of 2030. The widening of the A15 and the ambition to become climate neutral will affect the landscape experience in Overbetuwe. Both undoubtly mean an increase in the number of sound sources and noise pollution. The challenge here is the implementation of renewable energy technologies in the surroundings of the motorway, but also aims acoustic landscape quality. Keywords: Landscape architecture, landscape experience, Overbetuwe, traffic noise, soundscape provisional version 1. Introduction In a densely populated country, as the Netherlands, sound is ubiquitous in the landscape. The Dutch soundscape exists out of airports, wind turbines and natural areas. Neverthe- less, no sound is as present as the sound of cars passing by with an average speed of 130 kilometres per hour. We produce this sound every day when we travel between home and work. Depending on the direction of the wind, the noise of the motorway is audible in many places. The sound is all around us and is penetrated into our daily lives. Although sound can be perceived both as pleasant and unpleasant, the impact of noise pollution is immense. With the increase of infrastructure, as motor for economic growth, the soundscape of the Nether- lands changed drastically. Not only, has it become hard to find silence in our noisy country, but also natural environmental sounds, such as bird songs, are overwhelmed by traffic noise. 1.1. Case study: Overbetuwe Traffic noise is also dominating the soundscape of Overbetuwe. The region is intersected by three freeways, several highways and two train lines. The most important linear structures are the A15 and the Betuweroute, which transect the region from East to West (figure 1). The A15 connects Rotterdam and Enschede with each other. Parallel to this motorway the Betu- weroute is constructed (a freight railway). Both infrastructural networks form an important connection for the distribution of goods and services to Germany. The large-scale infrastructure thus connects spaces. It creates connectivity and eco- nomic development on the national level as well for the region. Nevertheless, the construc- tion of large scale infrastructure also includes negative side effects, such as large-scale developments near the motorway, noise nuisances, pollution and intersections of the land- scape without significance for the traditional structures in this landscape. These negative consequences will increase in the near future, since it is modelled that traffic congestion will occur when the A15 will not be adjusted to the increase of road users (Projectbureau ViA15, 2011). This not only affects transport within the region of Arnhem-Ni- jmegen, but also the distribution of goods between Randstad1 and Germany. In order to avoid congestion a new plans are introduced for the A15 trace. The plan connects the A15 with the 1. Randstad includes the Rotterdam harbour. Nevertheless, the distribution of goods will hardly affect the traffic congestion at the A15, since this will be transported by water and rail traffic. This means an increase of traffic noise produced by trucks on motorways, but an increase of noise produced by railways (Betuweroute) (Hav- enbedrijf Rotterdam, n.d.). provisional version A12 and current connection between Valburg and Ressen will be widened to 2x3 lanes (Pro- jectbureau ViA15, n.d.). Figure 1. Construction plan A15 (author; Projectbureau ViA15, n.d.b): Current connection between Valburg and Ressen will be widened to 2x3 lanes and the A15 will be connected to A12. Recently, the municipality of Overbetuwe introduced a new land use by setting the am- bition to become climate neutral by 2030 (Berns, Willems, & Berg, 2009; Libercé-Kruit & Uitbeijerse, 2010; Tempelman, Ahoud, Berns, Jaarsma, & Westerdiep, 2010). In other words, the municipality wants to reduce the emission of greenhouse gasses (CO2, etc.) to zero with regard to electricity and gas consumption by households, business and organizations(Berns et al., 2009). Within the research conducted for the author’s bachelor thesis both the im- plementation of renewable energy technologies in the surroundings of the motorway and acoustic landscape quality are taken into account. Nevertheless in the context of this pub- lication this paper focuses on the implementation of an acoustic gradient in the sustainable transport corridor of Overbetuwe. 1.2. Problem statement The widening of the A15 and the ambition to become climate neutral in 2030 will affect the landscape experience in Overbetuwe. Both undoubtly mean an increase in the number of sound sources and noise pollution. Moreover, is the appearance and spatial organisation of renewable energy technologies in the physical environment hardly taken into considering by landscape architects (Dobbelsteen & Stremke, 2013; Sijmons et al., 2008). It is therefore necessary to study the impact large scale infrastructure, energy transition and the use of different (renewable) energy sources, on landscapes around us. provisional version Dobbelsteen and Stremke (2013) are doing this by postulating that landscape architects should develop sustainable energy landscapes, rather than renewable energy landscapes. Although a lot has already been written on sustainable energy landscapes, and designers are anticipating on the topic, there is a need for a better integration of aesthetics and en- vironmental psychology into the shaping of sustainable energy landscapes (Dobbelsteen & Stremke, 2013). In other words, there should be a focus on the experience of sustainable energy landscapes. Traditionally, the focus of landscape experience, within the discipline of landscape ar- chitecture, was always on scenic quality (Blesser & Salter, 2007; Hedfors, 2003). Especially acoustic landscape experience has been hardly studied so far (Benfield, Belll, Troup, & Sod- erstrom, 2010; Hedfors, 2003). In case the acoustic environment was taken into account, it mostly was integrated in motorway design for noise reduction. Brown and Muhar (2004), therefore, encourage a more positive approach to sound. Accordance to them landscape design should focus on environments that produce sound that people prefer or consider as desirable. This thesis elaborates on both the knowledge gap and the statement of Brown and Muhar (2004) by studying present and (expected) future sound changes in Overbetuwe. 1.3. Research objective The research in this paper aims to explore the possibilities of landscape architecture to con- tribute the development of a sustainable transport corridor, with large scale-infrastructure and renewable energy technologies, which fosters visual and acoustic experience in Over- betuwe. The study focus is on the concept of soundscapes, which exist out of any acoustic landscape experience. Augoyard, Karlsson & Winkler (1999) define soundscapes in more de- tail as the “totality of sound phenomena that lead to perceptual, aesthetics and representa- tional comprehension of the sonic world” (Hedfors, 2003, p. 25). Although the receiving of sound is highly personal,Schafer (1997) indicated the existence of a favourable andunfavourable sound, namely hi-fi and lo-fi soundsystem. Between these systems a contrast between noise and silencecan be indicated.The hi-fi system is processing favourable signals:discrete sounds with a low ambient noise level that can beheard clearly (Schafer, 1997). Soundscapes where hi-fi sounddominates allows listeners to hear noises on distance. In a hi-fisoundscape hearing cannot be closed off at will, neverthelessa receiver is able to hear what he or she is willing to hear. Inother words, people have are able to filter out undesirablesound, while concentrating on what is desirable (Schafer,1997).This is not the case in lo-fi soundscapes, whereunfavourable sounds are produced. Here the amount ofsig- nals are overcrowded and exist out of loud sounds. Underthese conditions noise so much provisional version acoustic signals are presentthat people get lost in orientation. It causes a soundscape thatis unpleasant to be in. The lo-fi system is therefore closelyrelated to the term noise pollution. Most of the time such loud sounds are unfavourableand perceived as unwanted. Brown and Muhar (2004) madea distinction between wanted and unwanted sound signals.They state that wanted sounds are mainly produced in thenatural and human soundscape, such as church bells, soundsof nature, sounds of city vitality, food steps, sounds of runningwater music etc. (Brown & Muhar, 2004). Unwanted soundsare mostly present in the mechani- cal soundscape, such asroad traffic, human sounds, amplified music, machinerynoises, etc. (Brown & Muhar, 2004). Within the study the term noise pollution will be used to make a distinction between natural acoustic environment and the disruption of this acoustic environment by mechanical sound (noise pollution). Furthermore, audio audio‐visual interactions are taken